The Linux kernel uses different I/O scheduler depending if the block
device is a rotational device or not. Also it uses rotational devices
to add entropy to the random pool.
This patch add a rotational qdev property so that the block device can
be configured as a rotational device or a non-rotational device. Default
to true to not change the default behavior.
Signed-off-by: Aurelien Jarno <aurel...@aurel32.net>
---
blockdev.c | 4 ++++
include/hw/block/block.h | 4 +++-
2 files changed, 7 insertions(+), 1 deletion(-)
diff --git a/blockdev.c b/blockdev.c
index 4d8cdedd54..c914420641 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -4037,6 +4037,10 @@ QemuOptsList qemu_common_drive_opts = {
.name = BDRV_OPT_READ_ONLY,
.type = QEMU_OPT_BOOL,
.help = "open drive file as read-only",
+ },{
+ .name = "rotational",
+ .type = QEMU_OPT_BOOL,
+ .help = "rotational drive (off, on)",
},
THROTTLE_OPTS,
diff --git a/include/hw/block/block.h b/include/hw/block/block.h
index f3f6e8ef02..304a579eca 100644
--- a/include/hw/block/block.h
+++ b/include/hw/block/block.h
@@ -27,6 +27,7 @@ typedef struct BlockConf {
uint32_t cyls, heads, secs;
OnOffAuto wce;
bool share_rw;
+ bool rotational;
BlockdevOnError rerror;
BlockdevOnError werror;
} BlockConf;
@@ -56,7 +57,8 @@ static inline unsigned int get_physical_block_exp(BlockConf
*conf)
_conf.discard_granularity, -1), \
DEFINE_PROP_ON_OFF_AUTO("write-cache", _state, _conf.wce, \
ON_OFF_AUTO_AUTO), \
- DEFINE_PROP_BOOL("share-rw", _state, _conf.share_rw, false)
+ DEFINE_PROP_BOOL("share-rw", _state, _conf.share_rw, false), \
+ DEFINE_PROP_BOOL("rotational", _state, _conf.rotational, true)
#define DEFINE_BLOCK_CHS_PROPERTIES(_state, _conf) \
DEFINE_PROP_UINT32("cyls", _state, _conf.cyls, 0), \
--
2.11.0
